Inexpensive ph meter

Jorge Omar wrote...
I have an almost full box of short range, 0.5 pH paper, made in Germany.
I've tried it before going the cheap pH meter route.

Jorge

Jorge, what was unsatisfactory about the pH papers? I would have
expected them to be suitable and economical for occasional use.

John

John

In the range of inerest, say from 8 to 10, it's just the tonality of the
red band that becomes deeper. At least to my eyes/paper brand combo, it
was very hard to see the difference between a borax and a carbonate
solution, even placing two strips side by side.

Jorge

(John Stockdale) wrote in
om:

Jorge Omar wrote...
I have an almost full box of short range, 0.5 pH paper, made in
Germany. I've tried it before going the cheap pH meter route.

Jorge

Jorge, what was unsatisfactory about the pH papers? I would have
expected them to be suitable and economical for occasional use.

John

HI,

I read this thread with much interest. I have a related but different
question. For practical purposes in developing film and paper, what effect
does the different PH chemicals have on the results.

Other words, if I develop a film in developer with a PH of 7.0 how will it
differ from film developed in PH of 6.0 or 8.0. I know the PH is the amount of
acidity of the solution, but just never thought about this.

Lauvone

pH is a bit more complicated - 7 is neutral, below 7 it's acidic and
above 7 it's alkali.

Now, for almost all developers, the more alkali the solution is the more
active the developer will be.

Practical results of uping pH - shorter dev time for a given contrast or
higher contrast for the same dev time, and almost always more grain.

Jorge

(BLKnWHTwisner) wrote in
:

HI,

I read this thread with much interest. I have a related but different
question. For practical purposes in developing film and paper, what
effect does the different PH chemicals have on the results.

Other words, if I develop a film in developer with a PH of 7.0 how
will it differ from film developed in PH of 6.0 or 8.0. I know the PH
is the amount of acidity of the solution, but just never thought about
this.

Lauvone

Jorge Omar wrote:

pH is a bit more complicated - 7 is neutral, below 7 it's acidic and
above 7 it's alkali.

Now, for almost all developers, the more alkali the solution is the more
active the developer will be.

Practical results of uping pH - shorter dev time for a given contrast or
higher contrast for the same dev time, and almost always more grain.

Jorge

Hey guys,
Yeah pH paper is fine, however, you need someone with a good sense of
colour to differenciate the subtle changes. For instance, when I was
trying to make a good Carbonate/ Borax buffer to substitute for the
Metaborate alkaline buffer. I asked a friend with good colour sense to
try and tell associate the colour to the chart. She found it was very,
very close in colour to the pH of 10 but not quite. Jordan later tested
this solution to be pH 9.85 with his fancy gear that he uses.
I think there is a very high rate of colour-blindness (I know I am)
amongst males which probably accounts of a large % of this news-group -
therefore...

nicholas wrote in
:


Hey guys,
Yeah pH paper is fine, however, you need someone with a good sense of
colour to differenciate the subtle changes. For instance, when I was
trying to make a good Carbonate/ Borax buffer to substitute for the
Metaborate alkaline buffer. I asked a friend with good colour sense to
try and tell associate the colour to the chart. She found it was very,
very close in colour to the pH of 10 but not quite. Jordan later
tested this solution to be pH 9.85 with his fancy gear that he uses.
I think there is a very high rate of colour-blindness (I know I am)
amongst males which probably accounts of a large % of this news-group
- therefore...

Hum, I suppose your female friend is in her 20's, right?

Now I only have to convince my wife I need a young female assistent to
read pH paper color...
(-:

Jorge

For all practical purposes - keep pH according to the manufacturer's
specification.

Best advice I've seen yet on these responses. Each developer formulation is
designed for a specific level of activity based on the amount and specific
developing agents used, amount of sulfite, and bromide, etc. Playing with the
pH will not only shift the activity, but may also change grain, shadow detail,
contrast, etc. In other words, if you like what you get from a certain
developer, pH is something you DO NOT want to play with.

Someone mentioned it being important in E-6 first developer, but the color
developer is much more critical and pH changes will cause color shifts. It is
so critical that processors are advised to make minor pH adjustments based on
the sensitometric results of specially exposed control strips, because their
expensive $1000 meters are not sensitive or accurate enough to adjust based on
the actual pH reading. These labs pay more for a special electrode than the $50
hand held pH meters everyone is so ready to rely on.


Bernie

friend® wrote:
it depends, it is critical in BW developer of E6 process. it is
critical in d76 due to lack of restrainer (KBr). Color developers are
less critical, with changes going in yellow-blue direction, depending
on pH.
All developers are sensitive to pH, the higher the more active the
developer is. Then each developing substance react differently to
changes of pH. Atomal may work in pH 7, but developer with
hydroquinone will need 10, etc.
For all practical purposes - keep pH according to the manufacturer's
specification.



Some developers containing metol and hydroquinone have a pH less than 10. In
this case the hydroquinone does not act as a developer but acts to
reconstitute the used up metol.

On Fri, 12 Mar 2004 04:26:55 GMT, BertS wrote:

Some developers containing metol and hydroquinone have a pH less than 10. In
this case the hydroquinone does not act as a developer but acts to
reconstitute the used up metol.

The activity level of hydroquinone is diminished below 10pH
but that is not to say that it does not develop the halide. It just
doesn't have enough energy to initiate the halide reduction on it's
own.


Regards,

John S. Douglas, Photographer - http://www.darkroompro.com
Please remove the "_" when replying via email

On 11 Mar 2004 16:49:38 GMT, (BLKnWHTwisner)
wrote:


I read this thread with much interest. I have a related but different
question. For practical purposes in developing film and paper, what effect
does the different PH chemicals have on the results.

Increasing the pH will increased contrast, increase
granularity, produce a higher level of grain migration (degrades
sharpness) and soften the emulsion a little more than normal.

Should you want to see the results of developing using a
high-pH developer, I suggest developing TMX-100 in HC110 and use a low
pH developer such as D-23 or Microdol-X.

Regards,

John S. Douglas, Photographer - http://www.darkroompro.com
Please remove the "_" when replying via email